1. Field
The present disclosure relates to a vehicle battery unit and a harness holder.
2. Description of the Related Art
Hybrid vehicles, electric vehicles, or other electrically driven vehicles are mounted with high-voltage batteries as driving sources for the electric motors. The high-voltage batteries have sensors for detecting their voltage. A signal indicating the battery voltage detected by the sensors is sent to a control unit via a harness (hereinafter referred to as “VHB harness”) that provides a connection between the batteries and the control unit. Due to its analog circuitry, the VHB harness causes an error in battery voltage detected in the control unit side, depending on wire type, wire diameter, ambient temperature, or the state of mechanical connection with the sensors. Typically, thinner wire conductor, longer wire, greater changes in temperature, or greater number of mechanical connections tends to result in a larger error in battery voltage.
On the contrary, the control unit has a margin for threshold for detecting battery over-charging/over-discharging to allow for an error in battery voltage. In other words, a higher voltage detection accuracy for high-voltage batteries results in a smaller margin for battery control threshold, which leads to an improvement in vehicle energy efficiency. For this reason, it is desirable that the VHB harness be as thick and short as possible with smaller changes in temperature and fewer harness joints, while meeting requirements for restrictions on vehicle weight and interior space as well as assemblability.
International Publication No. 2010/098418 discloses a battery mounting structure in which a battery unit and a connection control unit for controlling electrical connections for the battery unit are disposed under a vehicle floor panel. The battery unit has two battery groups that are disposed with a space therebetween. The connection control unit is disposed inside the space, whereby the disposition of the connection control unit is maximized and harness length is minimized.